We read the work by Pringle at al. [1] with interest. One of the holy grails of Paediatric Emergency Medicine has been the rapid and reliable identification of the child with serious dehydration, and the converse, the ability to know when to safely discharge a child with a history of gastroenteritis. Recently there has been an external validation of a previously derived clinical dehydration scale by Bailey et al. [2]. It is encouraging to see this type of study as too often scoring systems are created without further testing. However we wondered about the generalisability of this result to routine Pediatric Emergency Care. Specifically we noted that in that study participating nurses undertook an additional training programme prior to study commencement. Is the score still valid if used by Pediatric Emergency Care staff who have not had this additional training? Our previous work has shown that experience and training in assessment may be vital in correctly assigning dehydration categories in children [3]. We found significant variability between junior doctors' assessments of dehydration compared to their seniors. We concluded previous studies on dehydration scoring systems may have benefited from well-trained staff and the introduction of these systems to naive health care professionals may not replicate initial results. The Pringle et al. study, while containing only a small number of subjects, challenges this conclusion again as it appears the care setting may influence the utility of the tool. The holy grail has yet to be found!

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